Pixie 1.5.7

Pixie 1.5.7 is out.

It includes the following imrpovements / fixes

GI/irradiancecache improvements:

maxError is 0.5 by default, turning it higher gives faster / smoother results (but less accurate). Lower, say 0.1 is suitable for high quality. Memory consumption and speed during GI baking are much improved. Note that the difference between 1.5.7 and 1.5.6 is improved compatibility of the way the maxError parameter works for tweaking the quality of the irradiance bakes.

OpenEXR support:

OpenEXR support has tentatively been added. Not all compilers / platforms appear to support this yet.

Pixie detects OpenEXR support, but the check for OpenEXR needs to be told where to look if the libs are not in the standard /usr/lib location.

It can also be told to link in statically. Both are options to configure:

These do the following (respectively)
backface culling is disabled for unshaded objects (they're shaded regardless)
hiding of unshaded grids is disabled
the dicing metric is determined in 3d raster-space rather than 2d raster

Either way, the visual result (which uses shaded grids) should be the same.

This is really useful for situations where the side-effects of running the shader are the important output of a render - eg irradiance cache generation. The generated caches will be valid from more angles than without these options

Other Changes / fixes:

* Corrected man page for texmake (the cube map face orders now match the program)
* RiTransformEnd should properly maintain the 'handedness' of the current transform
* fixed an issue where the RiSubdivisionSurface might alter the spline basis
functions in the current attributes
* String handles for lights are properly handled
* Environment lookup is fixed
* DESTDIR is respected for installing the shaders using the Makefile (supports RPM installations